QLK3-2002-01945 Improving arable production systems by expressing marine algal rubisco in crop plants (MARISCO)

Abstract

The project aims at increasing growth rates and yield of crop plants by improving their carbon fixing capabilities. It gathers the expertise of eight European laboratories with state-of-the-art structural and molecular biology techniques to map and characterise the carbon fixing enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) from marine arctic algae, which have been found to harbour a superior form of Rubisco. The feasibility of exploiting the results for agriculture will be tested in two model studies in which the endogenous Rubisco enzyme in the unicellular green alga Chlamydomonas reinhardtii and in crop plants will be replaced by the more efficient variant from marine algae. The research, which is supported by an SME involvement, will help European agriculture to stay competitive in a field which, because of its potential economic impact, is heavily investigated in the US and other western countries.

Objectives

The major goal of the project, to improve carbon fixation in crop plants, will be pursued by integrating the results of genetic, kinetic, phylogenetic and structural characterisation of the Rubisco carbon assimilating enzyme from marine arctic algae and by inserting identified potential superior enzymes into crop plants. One objective will be to identify, isolate and characterise highly specific Rubisco enzymes from marine algae. Secondly, the Rubisco genes, or parts of the genes, will be expressed in the unicellular green alga Chlamydomonas reinhardtii, and in the chloroplasts of crop plants. To achieve the objectives, a network of expert European laboratories will be installed, all specialised in Rubisco research, that form a critical mass absolutely required for this kind of research. Because the work is intended to improve the efficiency of crop production, it can not only contribute to strengthen the competitiveness of European agronomy but also at the same time help in efforts to preserve the environment and natural resources.

Activities

Rubisco is the primary catalyst for the assimilation of atmospheric carbon dioxide into the biosphere. Its function is compromised by an inherent competing oxygenation reaction and the result of this competition is a reduction of up to 50% in photosynthetic biomass production. The ability of Rubisco to discriminate between CO₂ and O₂ varies from species to species, dictated by evolutionary pressure towards the direction of a more efficient use of CO₂. Recent findings indicate that the most efficient Rubisco enzymes are found in some marine algae and diatoms, organisms known to be responsible for a significant portion of total primary production. We propose a systematic study of Rubisco from marine organisms in order to probe its function and to shed light on what influences specificity at the molecular level. We will set up routines for the collection and growth of marine micro-organisms from arctic waters.

Organisms for further investigation will be chosen according to their CO₂ fixing capability. Rubisco from the selected organisms will be purified and characterised in terms of kinetics, sequence, taxonomy, phylogeny and 3D structure. Rubisco enzymes with high selectivity towards CO₂ will be expressed, as a first attempt in the unicellular green alga Chlamydomonas reinhardtii, for which a simple chloroplast transformation protocol exists, and in the chloroplasts of crop plants to produce crops that assimilate CO₂ more efficiently.

The objectives will be achieved by coordinated collaboration between the partners that have an extensive and successful track record of working together. In addition to producing valuable results with implications both for agriculture and environment, the project will result in the development of valuable new basic research methodology in the fields of protein crystallography and chloroplast transformation.

Deliverables

The following deliverables are anticipated:

• mapping and full characterisation of highly CO₂-specific Rubisco enzymes from arctic marine algae with full-scale purification, crystallistation and structure determination.
• expression of highly specific Rubisco enzymes in the unicellular green alga Chlamydomonas reinhardtii as a model system.
• expression of highly specific Rubisco enzymes in chloroplasts of crop plants.
• formation of a network of European laboratories specialised in Rubisco research to achieve a critical mass for research and a basis for exploitation by European farmers and the agrochemical industry.

Contacts

Coordinator

• Inger ANDERSSON / Swedish University of Agricultural Sciences Department of Molecular Biology / SWEDEN

Participant

• Australian National University Research School of Biological Sciences / AUSTRALIA
• Vladimir MIRONOV / CropDesign N.V
• Martin PARRY / IACR-ROTHAMSTED UNITED KINGDOM
• The Agricultural University of Norway Laboratory of Microbial Gene Technology / NORWAY
• Joaquin MORENO / Universitat de Valencia Departament de Bioquimica i Biologia Molecular / SPAIN
• Uwe KLEIN / University of Oslo Department of Biology / NORWAY
• Hans Chr. EILERTSEN / University of Tromso Norwegian College of Fisheries Science / NORWAY